Mersen A720R4R - Mersen R-Rated fuses are current-limiting, high interrupting rating fuses intended for the short circuit protection of medium voltage motors and motor controllers. R-Rated fuses are back-up fuses that have a minimum interrupting rating, and must be coordinated with overload relays in combination motor starters. The motor starter manufacturer generally specifies the R-Rated fuse size. These fuses come with a 3 (size D) or 4 (size E) inch diameter barrels with ferrules and are mounted in spring reinforced clips. 7200 Volts 4 R A720R Series.
Mersen

A720R4R

Alternate Item Number: A720R4R

UPC: 782001800857

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Overview

Mersen A720R4R R-Rated fuses deliver unmatched short-circuit protection for medium-voltage motors and motor controllers operating at 7200 volts. Designed as back-up fuses with a minimum interrupting rating, these current-limiting devices must be coordinated with overload relays in combination motor starters—a critical requirement for safe and reliable motor operation in industrial environments. The A720R4R series features robust 3-inch (size D) or 4-inch (size E) diameter barrels with ferrule connections, ensuring secure mounting in spring-reinforced clips that resist vibration and maintain consistent electrical contact. Engineered for high-performance applications, these fuses provide exceptional interrupting capacity while protecting sensitive motor windings and downstream equipment from damaging fault currents. Medium-voltage motors are the backbone of countless industrial processes, from manufacturing and mining to water treatment and power generation. In these critical applications, even a brief overcurrent event can lead to catastrophic failure, unplanned downtime, and costly repairs. Mersen’s R-Rated fuses address this challenge by offering precise fault interruption with minimal let-through energy, preserving motor integrity and extending equipment lifespan. The A720R4R series is particularly well-suited for combination motor starters, where coordination with overload relays ensures seamless protection across the full range of operating conditions. Whether protecting large pumps, compressors, conveyors, or HVAC systems, these fuses provide the reliability demanded by modern industrial operations. Selecting the right fuse for medium-voltage motor protection requires careful consideration of voltage ratings, interrupting capacity, and coordination requirements. Mersen’s A720R4R fuses are rated for 7200 volts and designed to meet stringent interrupting rating standards, making them ideal for motors operating in harsh or high-fault environments. The ferrule-style connections simplify installation in spring-reinforced clips, which are engineered to withstand mechanical stress and thermal cycling without compromising performance. Unlike general-purpose fuses, R-Rated fuses are specifically tailored for motor applications, offering superior protection against short circuits while allowing normal motor inrush currents to pass without nuisance tripping. Industries such as oil and gas, chemical processing, pulp and paper, and metals manufacturing rely on Mersen’s expertise in electrical protection solutions. With decades of experience in fuse technology, Mersen has earned a reputation for innovation and reliability in medium-voltage protection systems. The A720R4R series exemplifies this commitment, combining robust construction with advanced materials to deliver consistent performance in even the most demanding conditions. Professionals trust Mersen fuses to safeguard their most critical assets, knowing that these devices are backed by comprehensive testing and adherence to industry standards. For engineers and maintenance teams tasked with designing or upgrading motor protection systems, the A720R4R series offers a proven solution that balances performance, safety, and longevity. By coordinating these back-up fuses with properly sized overload relays, you can achieve a protection scheme that minimizes downtime while maximizing equipment reliability. Whether you’re retrofitting an existing installation or specifying components for a new project, Mersen’s A720R4R R-Rated fuses provide the confidence of a trusted name in industrial electrical protection.
  • Current-limiting back-up fuses for 7200V medium-voltage motors and motor controllers
  • Available in 3-inch (size D) or 4-inch (size E) barrel diameters with ferrule connections
  • Mounted in spring-reinforced clips for secure, vibration-resistant installation
  • Must be coordinated with overload relays in combination motor starters
  • Designed for high interrupting ratings to protect against short-circuit faults

Specifications

Application
Short circuit protection of medium voltage motors and motor controllers.
Brand Name
Ferraz Shawmut
Connection
Ferrule
Connection Type
ferrules
Mounting
Clips
Mounting Type
Spring-reinforced clips
Series
A720R
Size
4 inch (Size E)
Special Features
The Amp-Trap&reg, and 9F60 R-Rated fuses are UL Recognized. Ferrule mounting for standard clips and interchangeability with other brands of fuses. Current-limiting for superior equipment protection. Metal embossed catalog number and manufacturing date for lasting identification. Hookeye for non load-break isolation by hookstick. On the 4.8kV an optional hookeye mounted in the factory is available. On all other 3&quot, barrel if a hookeye is required, use the operating eye 9F61AAW612. Blown-fuse indicator to give positive identification of open fuse. Amp-Trap&reg,: 3&quot, Barrel 2 lb tripped force - 0.50 Inch 9F60: 0.125 lb tripped force – 0.20 Inch
Standard
Amp-Trap&reg,: UL File E93367 9F60: UL File E191980
Type
Back-up current-limiting fuses R-Rated
Voltage Rating
7200 VAC
Package Dimensions (L x W x H)
21 IN x 3.1 IN x 3.1 IN
Package Dimensions (L x W x H)
53.34 cm x 7.874 cm x 7.874 cm
Package Weight (Imperial)
12.300 L
Package Weight (Metric)
5.579 kg
Fuse Block 600VAC 600VDC Class CC 30A 1/4in Quick Connect / Solder 90 angle screw Knob Panel Mount

GPM-SRR90

Fuse Block 600VAC 600VDC Class CC 30A 1/4in Quick Connect / Solder 90 angle screw Knob Panel Mount
Fuse Holder UltraSafe™ 800VAC 1000VDC UL Fuse size 14x51 1-Pole Visual Indicator Microswitch Pressure Plate IP20

C331156

Fuse Holder UltraSafe™ 800VAC 1000VDC UL Fuse size 14x51 1-Pole Visual Indicator Microswitch Pressure Plate IP20
Fuse Block 1500VAC 1500VDC 400A 1-Pole Stud M8

1SCM8

Fuse Block 1500VAC 1500VDC 400A 1-Pole Stud M8
Fuse Holder Modulostar® Size 10x38 IEC 690VAC 690VDC 3-Pole IP20

E1062696

Fuse Holder Modulostar® Size 10x38 IEC 690VAC 690VDC 3-Pole IP20
POWR-JAW clamps improve the contact between fuse and clip. The unnecessary heat from poor contact due to the loss of spring force in the clips can cause nuisance fuse opening and premature aging of surrounding components. High temperature phenolic resin knob designed for the most severe environments 7 sizes to provide effective coverage. Simple design makes installation easy.

LCC5

POWR-JAW clamps improve the contact between fuse and clip. The unnecessary heat from poor contact due to the loss of spring force in the clips can cause nuisance fuse opening and premature aging of surrounding components. High temperature phenolic resin knob designed for the most severe environments 7 sizes to provide effective coverage. Simple design makes installation easy.
9F61 Size B Clips 1.6in

9F61BWW460

9F61 Size B Clips 1.6in

Frequently Asked Questions about Mersen

What industries and applications are Mersen products used for?

Mersen products are used across diverse industrial sectors including solar power, electric vehicles, buildings/construction, industrial automation, power distribution, HVAC, elevators, telecommunications, and specialty manufacturing. Key application areas include circuit protection, surge protection, battery module protection, electrical safety systems, and power management for residential, commercial, and utility-scale installations.

What are the main product lines offered by Mersen?

Mersen offers five primary electrical power product lines: IEC and UL/CSA Fuses and Fusegear, Surge Protection, Low Voltage Disconnect Switches, Power Distribution Blocks, and Engineered Solutions. Their comprehensive range includes specialized components like high-speed fuses, modular fuse holders, surge arresters, and custom-engineered electrical protection systems for industrial and power management applications.

What are the key features of Mersen products?

Mersen products feature advanced electrical protection and power management solutions with key characteristics including finger-safe design, compact modularity, and high-performance safety features. Their product lines span electrical power components like fuses, surge protection, power distribution blocks, and specialized solutions for industrial, solar, and building applications. Critical features include UL/CSA approvals, high short-circuit current ratings, and innovative technologies like the Fuse Control™ program that minimize electrical risks and optimize system performance.

What environmental ratings do Mersen products have?

Mersen products meet rigorous environmental ratings across multiple standards, including UL 508A Type 1, 2, 3, 4, 4X, 12, and 13, CSA Type 1, 2, 3, 4, 4X, 12, and 13, and NEMA Type 1, 2, 3, 4, 4X, 12, and 13. They feature IEC 60529 IP66 protection, with enhanced UV inhibitors for outdoor weathering and operating temperatures ranging from -40°C to 130°C (-40°F to 266°F). These ratings ensure superior protection in wet, corrosive, and challenging industrial environments.

What accessories are available for Mersen products?

Mersen offers multiple accessories for their fuse blocks and systems, including safety pullers (DFC3M and DFC3LP), DIN-rail adapters (DRM), bus bars, auxiliary contacts, and specialized mounting hardware. Key accessories include the DFC3M safety puller for 1-1/2" x 13/32" midget or Class CC fuses, the DRM adapter for mounting 303 series fuse blocks on DIN-rail, and UltraSafe fuse module accessories like bus bars and auxiliary contacts that enable module interconnection and monitoring.

How are Mersen products typically installed?

Mersen products are typically installed in electrical distribution systems, control panels, and industrial automation environments using multiple mounting options. These include service entrance panel mounting, distribution panel installation, control panel DIN rail mounting, and custom engineered solutions like Fused Coordination Panelboards. Installation depends on the specific product type, such as fuses, surge protective devices, or switches, and is designed to provide electrical protection and circuit safety in various industrial and commercial applications.

What certifications and standards do Mersen products comply with?

Mersen products are certified to multiple international standards, including UL (Underwriters Laboratories), CSA (Canadian Standards Association), CCC (China Compulsory Certification), and EAC (Eurasian Conformity). Our products meet rigorous safety and performance standards for industrial applications across North America, China, Russia, and other global markets, ensuring compliance and reliability in electrical power and advanced materials solutions.

What technical support does Mersen offer?

Mersen provides comprehensive technical support through multiple channels, including technical experts located in your time zone who can assist with product selection, application guidance, and troubleshooting. Their Fuse Control™ program offers a free Fuse Inventory Audit & Analysis, and customers can access technical resources through their sales representatives and online platform ep.mersen.com.